It's about the proper behavior for a human being, in all circumstances.
Put two men on separate desert islands, and come back in a year or two. One is living in a compound made of trees, wearing clothes made of skins, with a water supply arranged, and clever devices built to make his life easier. The other, if he is still alive, is naked in the underbrush, surviving on fallen fruit and insects. The first greets his rescuers by raising a makeshift flag. The second one gibbers and tries to bite.
What's the difference? A code of behavior, and a belief that when it comes down to it, how you act has damn little to do with what other people do or say. It's the thing that makes prisoners of war shave every morning. It's remembering what makes people different from animals, and why.
"If it feels good, do it" was the mantra of part of a generation, including many libertarians. It's not enough to live by, and that it hurts no one else doesn't make it a standard of behavior to emulate.
Someone said something along the lines of "morality is what you do when nobody is looking." Someone else said, "Morality is what you do when the law isn't making you do it."
Ayn Rand wrote a pretty good article called "Apollo and Dionysus" that covered some of this issue. The introduction:
On July 16, 1969, one million people, from all over the country, converged on Cape Kennedy, Florida, to witness the launching of Apollo 11 that carried astronauts to the moon.
On August 15, 300,000 people, from all over the country, converged on Bethel, New York, near the town of Woodstock, to witness a rock music festival.
These two events were news, not philosophical theory. These were facts of our actual existence, the kinds of facts—according to both modern philosophers and practical businessmen—that philosophy has nothing to do with.
But if one cares to understand the meaning of these two events—to grasp their roots and their consequences—one will understand the power of philosophy and learn to recognize the specific forms in which philosophical abstractions appear in our actual existence.